[PATCH v3 01/16] iommufd/viommu: Introduce IOMMUFD_OBJ_VDEVICE and its related struct

[Nicolin Chen]

Introduce a new IOMMUFD_OBJ_VDEVICE to represent a physical device, i.e.
iommufd_device (idev) object, against an iommufd_viommu (vIOMMU) object in
the VM. This vDEVICE object (and its structure) holds all the information
and attributes in a VM, regarding the device related to the vIOMMU.

As an initial patch, add a per-vIOMMU virtual ID. This can be:
 - Virtual StreamID on a nested ARM SMMUv3, an index to a Stream Table
 - Virtual DeviceID on a nested AMD IOMMU, an index to a Device Table
 - Virtual ID on a nested Intel VT-D IOMMU, an index to a Context Table
Potentially, this vDEVICE structure can hold some vData for Confidential
Compute Architecture (CCA).

Add a pair of vdevice_alloc and vdevice_free in struct iommufd_viommu_ops
to allow driver-level vDEVICE structure allocations.

Similar to iommufd_vdevice_alloc, add an iommufd_vdevice_alloc helper so
IOMMU drivers can allocate core-embedded style structures.

Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
 drivers/iommu/iommufd/iommufd_private.h |  1 +
 include/linux/iommufd.h                 | 31 +++++++++++++++++++++++++
 drivers/iommu/iommufd/viommu_api.c      | 14 +++++++++++
 3 files changed, 46 insertions(+)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index c80d880f8b6a..0c56a467e440 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -132,6 +132,7 @@ enum iommufd_object_type {
 	IOMMUFD_OBJ_ACCESS,
 	IOMMUFD_OBJ_FAULT,
 	IOMMUFD_OBJ_VIOMMU,
+	IOMMUFD_OBJ_VDEVICE,
 #ifdef CONFIG_IOMMUFD_TEST
 	IOMMUFD_OBJ_SELFTEST,
 #endif
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 069a38999cdd..510fc961a9ad 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -75,13 +75,30 @@ struct iommufd_viommu {
 	unsigned int type;
 };
 
+struct iommufd_vdevice {
+	struct iommufd_object obj;
+	struct iommufd_ctx *ictx;
+	struct iommufd_device *idev;
+	struct iommufd_viommu *viommu;
+	u64 id; /* per-vIOMMU virtual ID */
+};
+
 /**
  * struct iommufd_viommu_ops - vIOMMU specific operations
  * @free: Free all driver-specific parts of an iommufd_viommu. The memory of the
  *        vIOMMU will be free-ed by iommufd core after calling this free op.
+ * @vdevice_alloc: Allocate a driver-managed iommufd_vdevice to init some driver
+ *                 specific structure or HW procedure. Note that the core-level
+ *                 structure is filled by the iommufd core after calling this op.
+ * @vdevice_free: Free a driver-managed iommufd_vdevice to de-init its structure
+ *                or HW procedure. The memory of the vdevice will be free-ed by
+ *                iommufd core.
  */
 struct iommufd_viommu_ops {
 	void (*free)(struct iommufd_viommu *viommu);
+	struct iommufd_vdevice *(*vdevice_alloc)(struct iommufd_viommu *viommu,
+						 struct device *dev, u64 id);
+	void (*vdevice_free)(struct iommufd_vdevice *vdev);
 };
 
 #if IS_ENABLED(CONFIG_IOMMUFD)
@@ -103,6 +120,8 @@ int iommufd_vfio_compat_set_no_iommu(struct iommufd_ctx *ictx);
 struct iommufd_viommu *
 __iommufd_viommu_alloc(struct iommufd_ctx *ictx, size_t size,
 		       const struct iommufd_viommu_ops *ops);
+struct iommufd_vdevice *
+__iommufd_vdevice_alloc(struct iommufd_ctx *ictx, size_t size);
 #else /* !CONFIG_IOMMUFD */
 static inline struct iommufd_ctx *iommufd_ctx_from_file(struct file *file)
 {
@@ -150,6 +169,12 @@ __iommufd_viommu_alloc(struct iommufd_ctx *ictx, size_t size,
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
+
+static inline struct iommufd_vdevice *
+__iommufd_vdevice_alloc(struct iommufd_ctx *ictx, size_t size)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
 #endif /* CONFIG_IOMMUFD */
 
 /*
@@ -163,4 +188,10 @@ __iommufd_viommu_alloc(struct iommufd_ctx *ictx, size_t size,
 						struct drv_struct, member)),   \
 					    ops),                              \
 		     struct drv_struct, member)
+#define iommufd_vdevice_alloc(ictx, drv_struct, member)                        \
+	container_of(__iommufd_vdevice_alloc(ictx,                             \
+					     sizeof(struct drv_struct) +       \
+					     BUILD_BUG_ON_ZERO(offsetof(       \
+						struct drv_struct, member))),  \
+		     struct drv_struct, member)
 #endif
diff --git a/drivers/iommu/iommufd/viommu_api.c b/drivers/iommu/iommufd/viommu_api.c
index c1731f080d6b..8419df3b658c 100644
--- a/drivers/iommu/iommufd/viommu_api.c
+++ b/drivers/iommu/iommufd/viommu_api.c
@@ -55,3 +55,17 @@ __iommufd_viommu_alloc(struct iommufd_ctx *ictx, size_t size,
 	return viommu;
 }
 EXPORT_SYMBOL_NS_GPL(__iommufd_viommu_alloc, IOMMUFD);
+
+struct iommufd_vdevice *
+__iommufd_vdevice_alloc(struct iommufd_ctx *ictx, size_t size)
+{
+	struct iommufd_object *obj;
+
+	if (WARN_ON(size < sizeof(struct iommufd_vdevice)))
+		return ERR_PTR(-EINVAL);
+	obj = iommufd_object_alloc_elm(ictx, size, IOMMUFD_OBJ_VDEVICE);
+	if (IS_ERR(obj))
+		return ERR_CAST(obj);
+	return container_of(obj, struct iommufd_vdevice, obj);
+}
+EXPORT_SYMBOL_NS_GPL(__iommufd_vdevice_alloc, IOMMUFD);
-- 
2.43.0